The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
Free tracker included with every download this week
What Is Considered gradual weight management?
gradual weight management is typically defined as losing more than 1 kg (2.2 lbs) per week. The NHS recommends losing weight at a slower, more sustainable rate of 0.5 to 1 kg per week for most adults. Losing weight very quickly can increase risks of muscle loss, nutritional deficiencies, gallstones, and metabolic changes. Understanding what constitutes gradual weight management—and why it matters for your health—helps you set realistic weight management goals and choose safe approaches to weight loss UK.
10,000+ calculations today · NHS-aligned thresholds · 100% free
Calculate Your BMI Instantly
Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
NHS Safe Weight Loss Rate and Rapid Loss Definition
Safe weight loss rate: The NHS recommends losing 0.5 to 1 kg (1 to 2 lbs) per week as the safest, most sustainable approach.
gradual weight management definition: Losing more than 1.5 kg per week, or more than 6 kg per month, is generally considered rapid. Very rapid loss (more than 3 kg per week) requires medical supervision.
Why the difference matters: gradual weight management often involves losing water and muscle alongside fat, whereas gradual loss preserves muscle mass. A calorie deficit of around 500 kcal daily typically produces the recommended 0.5 kg weekly loss.
Faster loss is possible under medical supervision—for example, very low calorie diets (under 800 kcal daily) are sometimes prescribed by specialist weight management services. However, these carry increased risks and require close monitoring. Use our free BMI calculator above to establish your current weight status, then set realistic goals based on this safe rate.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
Health Risks of gradual weight management
Losing weight too quickly can trigger several health complications: muscle loss (rapid loss is often 25–30% muscle, not just fat), nutritional deficiencies (lack of essential vitamins and minerals), gallstones (rapid fat loss can cause gallbladder problems), metabolic slowdown (your body adapts by burning fewer calories), and fatigue, hair loss, and hormonal changes.
For sustainable weight management UK, slower loss is more effective long-term. If you're considering prescription weight loss medication such as GLP-1 injections, your prescriber will assess whether this is appropriate and monitor you closely. Try our GLP-1 weight loss calculator to explore potential results with medical support at safe rates.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
What's the difference between rapid and normal weight loss?
Normal weight loss is 0.5–1 kg per week. Rapid loss is more than 1.5 kg per week. Normal loss preserves muscle and is sustainable; rapid loss often includes muscle loss and carries health risks. The NHS recommends the normal rate for safety.
Can gradual weight management be done safely under medical supervision?
Yes, in some cases. Very low calorie diets (under 800 kcal daily) are sometimes prescribed by specialist weight management services for specific conditions. These require close GP monitoring, regular blood tests, and nutritional support. Always consult your GP before attempting any gradual weight management approach.
Why do people lose weight very quickly at the start of a diet?
Initial rapid loss is usually water and glycogen (carbohydrate stores), not fat. Once these deplete, loss typically slows to the expected rate. This is normal and not a sign that your diet isn't working. Sustainable fat loss takes time.
Does prescription weight loss medication cause gradual weight management?
GLP-1 medications like Wegovy may support weight loss of around 14–15% body weight over several months when combined with diet and exercise. This is gradual, not rapid. Results vary by individual. Your prescriber will monitor your progress and adjust doses based on your response.
When should I contact my GP about gradual weight management?
Contact your GP if you're losing more than 1.5 kg per week unintentionally, experiencing severe fatigue, dizziness, or hair loss, or if you're considering gradual weight management and want medical guidance. Your GP can assess whether this is safe for you and monitor for complications.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.